The present invention relates to vehicle transporters, such as trucks, trailers, railcars and the like, which have vehicle support members lockable at different elevations on the transporter.
Conventional vehicle transporters are normally equipped with vehicle support members movable between different elevations by means of lifting motors such as fluid power cylinder assemblies. Vehicle transporters of this type, such as truck/trailer combinations, are capable of elevating and orienting numerous automobiles in tightly stacked configurations to maximize the payload. However, a significant drawback of such transporters is the time required to lock each vehicle support member in its elevated position during loading of the transporter, and to unlock each support member during unloading. These tasks normally require manual insertion of individual locking pins into the transporter structural members after the vehicle support members have been raised to their desired elevated positions during loading of the transporter, and manual removal of such pins prior to lowering the vehicle support members during unloading. The pin locations may be as high as twelve feet off the ground, requiring the operator to climb up onto the transporter to access the pins for insertion or removal. Adding to the time consumption is the fact that the pins can be inserted to lock the vehicle support members only if pin-receiving holes are first properly aligned by the lifting motors. Moreover, the pins can be removed to unlock the vehicle support members only if the weight of the support members has been adequately removed from the pins by the lifting motors. This requires careful coordination between the control of the lifting motors at ground level and the manipulation of the pins at elevated positions.
In addition to the excessive time required to insert and remove the manual locking pins, a further drawback to their use is the possibility that a fluid cylinder may fail while the associated vehicle support member is elevated, either before a locking pin has been inserted during the loading process, or after a locking pin has been removed during the unloading process. In such case, workmen in close proximity to the elevated vehicles during the loading and unloading processes are susceptible to injury.
The foregoing problems are not solved by the conventional expedient of simply spring-biasing the pins toward their locked positions, because manual manipulation of the pins at high elevations would still be required. Locking systems such as those described in the Background of the Invention and Description of the Preferred Embodiment of U.S. Pat. No. 5,755,540, which is incorporated herein by reference, can solve some of the foregoing problems by their remote operation of locks. However, they cannot apply a resilient force to unlock a locking member, nor can they provide the economical reliability of a simple manual system.
To solve the foregoing problems, a vehicle transporter is provided which has a frame with at least one vehicle support member movable by a lifting motor along a structural member between different elevations. At least one locking member interacts between the vehicle support member and the structural member, the locking member having a locked position preventing movement of the vehicle support member along the structural member, and an unlocked position permitting such movement. A resiliently-yieldable biasing device is selectively operable by a controller to urge the locking member resiliently at least toward the unlocked position, and preferably alternatively toward the locked position as well.